It is well known in motor vehicles to provide an air dam mounted on the underside of the front end structure of the vehicle body forwardly of the front wheels. The air dam structure lowers the aerodynamic drag of the vehicle and also improves the front end appearance of the vehicle by concealing from view underhanging elements of the front end suspension and the engine.
In the prior art the air dam is conventionally comprised of a molded plastic deflector panel which has a central portion extending generally transversely of the vehicle body and wraparound corner portions at each outer end which extend longitudinally of the vehicle for a short distance. Such an air dam may be comprised of a one piece plastic molding or the central portion may be molded separately from the corner portions.
The use of plastic for the front air dam is beneficial because, by proper selection of the plastic and the design of the shape of the deflector panel, the deflector panel is yieldable upon engagement against a concrete parking bumper or other obstruction. However, such a plastic deflector panel necessarily has limits to its yieldability and a further forward movement of the vehicle after engagement with the obstruction can lead to breakage of the deflector panel. In other circumstances, depending upon the height of the obstruction, the deflector panel is known to pass over the obstruction, but then when the vehicle is backed away from the obstruction the deflector panel becomes hung up and is subject to breakage.
It would be desirable to provide the vehicle operator with a warning of the impending possibility of damage to the deflector panel.
According to the present invention an air dam comprised of a molded plastic deflector panel is mounted beneath the front end structure of the vehicle forwardly of the front wheels. The deflector panel is subject to engagement with a parking bumper or other obstruction and is elastically yieldably movable upon such engagement within a certain range of elastic deformation and is subject to breakage upon deformation beyond the limit of the range of elastic deformation. A switch is mounted on the front end structure rearwardly of the molded plastic deflector panel and has an associated sensor which is operatively associated with the deflector panel and is adapted to actuate the switch in response to yielding movement of the deflector panel within the range of elastic deformation. A signal device is responsive to actuation of the switch in order to warn the vehicle operator that an obstruction has been engaged causing yieldable movement of the deflector panel within the range of elastic deformation and that a further forward movement of the vehicle may exceed the limit of the range of elastic deformation and thereby subject the deflector panel to breakage. The air deflector panel may be comprised of independently movable generally transverse central portion and wraparound corner portions at each end thereof in which case a switch means and associated sensor means may be provided for each of the independently movable portions of the deflector panel.
Accordingly, the object, feature and advantage of the invention resides in the provision of a switch and sensor means mounted on the front end structure rearwardly of a molded plastic deflector panel for warning the vehicle operator that an obstruction has been engaged and that the air dam has been yieldably moved within a range of elastic yieldable movement and that a further forward movement of the vehicle may exceed the limit of the range of elastic deformation and subject the deflector panel to breakage.
A further feature, object and advantage of the invention resides in the provision of a switch and sensor associated with each independently movable portion of the vehicle underbody air dam whereby to warn the vehicle operator of elastic yielding movement of that portion of the deflector panel so that the occupant may prevent a further forward movement of the vehicle which may exceed the limit of the range of elastic deformation and subject a portion of the deflector panel to breakage.